1. Field
Embodiments described herein relate generally to a brushless motor driving circuit and a brushless motor driving system.
2. Background Art
A conventional brushless motor driving circuit detects the position (phase) of the brushless motor from the induced voltage of the brushless motor by means of a comparator.
The brushless motor driving circuit may turn off the output of the power device, which drives the brushless motor, to make the brushless motor idle. In such a case, the reference voltage of the comparator becomes unstable, and the induced voltage of the motor decreases when the motor rotates at a low speed.
As the induced voltage of the brushless motor decreases out of the input range of the comparator, it becomes unable to detect the position of the motor.
If this occurs, the brushless motor driving circuit can fail to restart the brushless motor, or a loss of synchronization or an unusual noise can occur when the brushless motor driving circuit restarts the brushless motor.